This document covers the following topics:
A field (userdefined variable or database field) which is to be used as an operand in an arithmetic operation must be defined with one of the following formats:
Format  

N  Numeric unpacked 
P  Packed numeric 
I  Integer 
F  Floating point 
D  Date 
T  Time 
Note:
For reporting mode: A field which is to be used as an operand in an arithmetic
operation must have been previously defined. A userdefined variable or database field
used as a result field in an arithmetic operation need not have been previously
defined.
All userdefined variables and all database fields defined in a DEFINE DATA
statement are initialized
to the appropriate zero or blank value when the program is invoked for execution.
Data transfer is performed with a MOVE
or COMPUTE
statement. The following table summarizes the data
transfer compatibility of the formats an operand may take.
Sending Field Format  Receiving Field Format  

N or P  A  U  Bn (n<5)  Bn (n>4)  I  L  C  D  T  F  G  O  
N or P  Y  [ 2 ]  [ 14 ]  [ 3 ]    Y        Y  Y     
A    Y  [ 13 ]  [ 1 ]  [ 1 ]                 
U    [ 11 ]  Y  [ 12 ]  [ 12 ]                 
Bn (n<5)  [ 4 ]  [ 2 ]  [ 14 ]  [ 5 ]  [ 5 ]  Y        Y  Y     
Bn (n>4)    [ 6 ]  [ 15 ]  [ 5 ]  [ 5 ]                 
I  Y  [ 2 ]  [ 14 ]  [ 3 ]    Y        Y  Y     
L    [ 9 ]  [ 16 ]        Y             
C                Y           
D  Y  [ 9 ]  [ 16 ]  Y    Y      Y  [7]  Y     
T  Y  [ 9 ]  [ 16 ]  Y    Y      [ 8 ]  Y  Y     
F  Y  [ 9 ] [ 10 ]  [ 10 ] [ 16 ]  [ 3 ]    Y        Y  Y     
G                        Y   
O                          Y 
Where:
Y  Indicates data transfer compatibility. 

  Indicates data transfer incompatibility. 
[ ]  Numbers in brackets [ ] refer to the corresponding rule for data transfer given below. 
The following rules apply to converting data values:
Alphanumeric to binary:
The value will be moved byte by byte from left to right. The result may be
truncated or padded with trailing blank characters depending on the length defined
and the number of bytes specified.
(N,P,I) and binary (length 14) to
alphanumeric:
The value will be converted to unpacked form and moved into the alphanumeric field
left justified, that is, leading zeros will be suppressed and the field will be
filled with trailing blank characters. For negative numeric values, the sign will be
converted to the hexadecimal notation Dx
.
Any decimal point in the numeric value will be ignored. All digits before and after
the decimal point will be treated as one integer value.
(N,P,I,F) to binary (14 bytes):
The numeric value will be converted to binary (4 bytes). Any decimal point in the
numeric value will be ignored (the digits of the value before and after the decimal
point will be treated as an integer value). The resulting binary number will be
positive or a two's complement of the number depending on the sign of the value.
Binary (14 bytes) to numeric:
The value will be converted and assigned to the numeric value right justified,
that is, with leading zeros. (Binary values of the length 13 bytes are always
assumed to have a positive sign. For binary values of 4 bytes, the leftmost bit
determines the sign of the number: 1=negative, 0=positive.) Any decimal point in the
receiving numeric value will be ignored. All digits before and after the decimal
point will be treated as one integer value.
Binary to binary:
The value will be moved from right to left byte by byte. Leading binary zeros will
be inserted into the receiving field.
Binary (>4 bytes) to alphanumeric:
The value will be moved byte by byte from left to right. The result may be
truncated or padded with trailing blanks depending on the length defined and the
number of bytes specified.
Date (D) to time (T):
If date is moved to time, it is converted to time assuming time 00:00:00:0.
Time (T) to date (D):
If time is moved to date, the time information is truncated, leaving only the date
information.
L,D,T,F to A:
The values are converted to display form and are assigned left justified.
F:
If F is assigned to an alphanumeric or Unicode field which is too short, the
mantissa is reduced accordingly.
Unicode to alphanumeric:
The Unicode value will be converted to alphanumeric character codes according to
the default code page (value of the system variable *CODEPAGE
) using the International
Components for Unicode (ICU) library. The result may be truncated or padded with
trailing blank characters, depending on the length defined and the number of bytes
specified.
Unicode to binary:
The value will be moved code unit by code unit from left to right. The result may
be truncated or padded with trailing blank characters, depending on the length
defined and the number of bytes specified. The length of the receiving binary field
must be even.
Alphanumeric to Unicode:
The alphanumeric value will be converted from the default code page to a Unicode
value using the International Components for Unicode (ICU) library. The result may
be truncated or padded with trailing blank characters, depending on the length
defined and the number of code units specified.
(N,P,I) and binary (length 14) to Unicode:
The value will be converted to unpacked form from which an alphanumeric value will
be obtained by suppression of leading zeros. For negative numeric values, the sign
will be converted to the hexadecimal notation
Dx
. Any decimal point in the numeric value
will be ignored. All digits before and after the decimal point will be treated as
one integer value. The resulting value will be converted from alphanumeric to
Unicode. The result may be truncated or padded with trailing blank characters,
depending on the length defined and the number of code units specified.
Binary (>4 bytes) to Unicode:
The value will be moved byte by byte from left to right. The result may be
truncated or padded with trailing blanks, depending on the length defined and the
number of bytes specified. The length of the sending binary field must be even.
L,D,T,F to U:
The values are converted to an alphanumeric display form. The resulting value will
be converted from alphanumeric to Unicode and assigned left justified.
If source and target format are identical, the result may be truncated or padded with trailing blank characters (format A and U) or leading binary zeros (format B) depending on the length defined and the number of bytes (format A and B) or code units (format U) specified.
See also Using Dynamic Variables.
The following rules apply to field truncation and rounding:
Highorder numeric field truncation is allowed only when the digits to be truncated are leading zeros. Digits following an expressed or implied decimal point may be truncated.
Trailing positions of an alphanumeric field may be truncated.
If the option ROUNDED
is specified, the last position of the result will
be rounded up if the first truncated decimal position of the value being assigned
contains a value greater than or equal to 5. For the result precision of a division,
see also Precision of Results of
Arithmetic Operations.
The following table shows the format and length of the result of an arithmetic operation:
I1  I2  I4  N or P  F4  F8  

I1  I1  I2  I4  P*  F4  F8 
I2  I2  I2  I4  P*  F4  F8 
I4  I4  I4  I4  P*  F4  F8 
N or P  P*  P*  P*  P*  F4  F8 
F4  F4  F4  F4  F4  F4  F8 
F8  F8  F8  F8  F8  F8  F8 
On a mainframe computer, format/length F8 is used instead of F4 for improved precision of the results of an arithmetic operation.
P* is determined from the integer length and precision of the operands individually for each operation, as shown under Precision of Results of Arithmetic Operations.
The following decimal integer lengths and possible values are applicable for format I:
Format/Length  Decimal Integer Length  Possible Values 

I1  3  128 to 127 
I2  5  32768 to 32767 
I4  10  2147483648 to 2147483647 
The following topics are covered below:
Floatingpoint numbers (format F) are represented as a sum of powers of two (as are integer numbers (format I)), whereas unpacked and packed numbers (formats N and P) are represented as a sum of powers of ten.
In unpacked or packed numbers, the position of the decimal point is fixed. In floatingpoint numbers, however, the position of the decimal point (as the name indicates) is "floating", that is, its position is not fixed, but depends on the actual value.
Floatingpoint numbers are essential for the computing of trigonometric functions or mathematical functions such as sinus or logarithm.
Due to the nature of floatingpoint numbers, their precision is limited:
For a variable of format/length F4, the precision is limited to approximately 7 digits.
For a variable of format/length F8, the precision is limited to approximately 15 digits.
Values which have more significant digits cannot be represented exactly as a floatingpoint number. No matter how many additional digits there are before or after the decimal point, a floatingpoint number can cover only the leading 7 or 15 digits respectively.
An integer value can only be represented exactly in a variable of format/length F4 if its absolute value does not exceed 2 ^{23} 1.
When an alphanumeric, unpacked numeric or packed numeric value is converted to floatingpoint format (for example, in an assignment operation), the representation has to be changed, that is, a sum of powers of ten has to be converted to a sum of powers of two.
Consequently, only numbers that are representable as a finite sum of powers of two can be represented exactly; all other numbers can only be represented approximately.
This number has an exact floatingpoint representation:
1.25 = 2^{0} + 2^{2}
This number is a periodic floatingpoint number without an exact representation:
1.2 = 2^{0} + 2^{3} + 2^{4} + 2^{7} + 2^{8} + 2^{11} + 2^{12} + ...
Thus, the conversion of alphanumeric, unpacked numeric or packed numeric values to floatingpoint values, and vice versa, can introduce small errors.
Because of different hardware architecture, the representation of floatingpoint numbers varies according to platforms. This explains why the same application, when run on different platforms, may return slightly different results when floatingpoint arithmetic are involved. The respective representation also determines the range of possible values for floatingpoint variables, which is (approximately)
±1.17 * 10^{38} to ±3.40 * 10^{38} for F4 variables,
±2.22 * 10^{308} to ±1.79 * 10^{308} for F8 variables.
Note:
The representation used by your pocket calculator may also be different from the
one used by your computer  which explains why results for the same computation may
differ.
With formats D (date) and T (time), only addition, subtraction, multiplication and division are allowed. Multiplication and division are allowed on intermediate results of additions and subtractions only.
Date/time values can be added to/subtracted from one another; or integer values (no decimal digits) can be added to/subtracted from date/time values. Such integer values can be contained in fields of formats N, P, I, D, or T.
The intermediate results of such an addition or subtraction may be used as a multiplicand or dividend in a subsequent operation.
An integer value added to/subtracted from a date value is assumed to be in days. An integer value added to/subtracted from a time value is assumed to be in tenths of seconds.
For arithmetic operations with date and time, certain restrictions apply, which are due to the Natural's internal handling of arithmetic operations with date and time, as explained below.
Internally, Natural handles an arithmetic operation with date/time variables as follows:
COMPUTE
resultfield = operand1 +/
operand2

The above statement is resolved as:
intermediateresult = operand1
+/ operand2
resultfield =
intermediateresult
That is, in a first step Natural computes the result of the addition/subtraction, and in a second step assigns this result to the result field.
More complex arithmetic operations are resolved following the same pattern:
COMPUTE
resultfield = operand1 +/
operand2 +/ operand3 +/
operand4

The above statement is resolved as:
intermediateresult1 =
operand1 +/
operand2
intermediateresult2 =
intermediateresult1 +/
operand3
intermediateresult3 =
intermediateresult2 +/
operand4
resultfield =
intermediateresult3
The resolution of multiplication and division operations is similar to the resolution for addition and subtraction.
The internal format of such an intermediate result depends on the formats of the operands, as shown in the tables below.
The following table shows the format of the intermediate result of an addition
(intermediateresult =
operand1 + operand2
):
Format of operand1

Format of operand2

Format of intermediateresult


D  D  Di 
D  T  T 
D  Di, Ti, N, P, I  D 
T  D, T, Di, Ti, N, P, I  T 
Di, Ti, N, P, I  D  D 
Di, Ti, N, P, I  T  T 
Di, N, P, I  Di  Di 
Ti, N, P, I  Ti  Ti 
Di  Ti, N, P, I  Di 
Ti  Di, N, P, I  Ti 
The following table shows the format of the intermediate result of a subtraction
(intermediateresult =
operand1  operand2
):
Format of operand1

Format of operand2

Format of intermediateresult


D  D  Di 
D  T  Ti 
D  Di, Ti, N, P, I  D 
T  D, T  Ti 
T  Di, Ti, N, P, I  T 
Di, N, P, I  D  Di 
Di, N, P, I  T  Ti 
Di  Di, Ti, N, P, I  Di 
Ti  D, T, Di, Ti, N, P, I  Ti 
N, P, I  Di, Ti  P12 
The following table shows the format of the intermediate result of a multiplication
(intermediateresult =
operand1 * operand2
) or
division (intermediateresult =
operand1 / operand2
):
Format of operand1

Format of operand2

Format of intermediateresult


D  D, Di, Ti, N, P, I  Di 
D  T  Ti 
T  D, T, Di, Ti, N, P, I  Ti 
Di  T  Ti 
Di  D, Di, Ti, N, P, I  Di 
Ti  D  Di 
Ti  Di, T, Ti, N, P, I  Ti 
N, P, I  D, Di  Di 
N, P, I  T, Ti  Ti 
Di is a value in internal date format; Ti is a value in internal time format; such values can be used in further arithmetic date/time operations, but they cannot be assigned to a result field of format D (see the assignment table below).
In complex arithmetic operations in which an intermediate result of internal format Di or Ti is used as operand in a further addition/subtraction/multiplication/division, its format is assumed to be D or T respectively.
The following table shows which intermediate results can internally be assigned to which
result fields (resultfield =
intermediateresult
).
Format of resultfield

Format of intermediateresult

Assignment possible 

D  D, T  yes 
D  Di, Ti, N, P, I  no 
T  D, T, Di, Ti, N, P, I  yes 
N, P, I  D, T, Di, Ti, N, P, I  yes 
A result field of format D or T must not contain a negative value.
COMPUTE DATE1 (D) = DATE2 (D) + DATE3 (D) COMPUTE DATE1 (D) = DATE2 (D)  DATE3 (D)
These operations are not possible, because the intermediate result of the addition/subtraction would be format Di, and a value of format Di cannot be assigned to a result field of format D.
COMPUTE DATE1 (D) = TIME2 (T)  TIME3 (T) COMPUTE DATE1 (D) = DATE2 (D)  TIME3 (T)
These operations are not possible, because the intermediate result of the addition/subtraction would be format Ti, and a value of format Ti cannot be assigned to a result field of format D.
COMPUTE DATE1 (D) = DATE2 (D)  DATE3 (D) + TIME3 (T)
This operation is possible. First, DATE3
is subtracted from
DATE2
, giving an intermediate result of format Di; then, this intermediate
result is added to TIME3
, giving an intermediate result of format T; finally,
this second intermediate result is assigned to the result field DATE1
.
COMPUTE DATE1 (D) = DATE2 (D) + DATE3 (D) * 2 COMPUTE TIME1 (T) = TIME2 (T)  TIME3 (T) / 3
These operations are not possible, because the attempted multiplication/division is performed with date/time fields and not with intermediate results.
COMPUTE DATE1 (D) = DATE2 (D) + (DATE3(D)  DATE4 (D)) * 2
This operation is possible. First, DATE4
is subtracted from
DATE3
giving an intermediate result of format Di; then, this intermediate
result is multiplied by two giving an intermediate result of format Di; this intermediate
result is added to DATE2
giving an intermediate result of format D; finally,
this third intermediate result is assigned to the result field DATE1
.
If a format T value is assigned to a format D field, you must ensure that the time value contains a valid date component.
When doing arithmetic operations, the choice of field formats has considerable impact on performance:
For business arithmetic, only fields of format I (integer) should be used, if possible.
For scientific arithmetic, fields of format F (floating point) should be used, if possible.
In expressions where formats are mixed between numeric (N, P) and floating point (F), a conversion to floating point format is performed. This conversion results in considerable CPU load. Therefore it is recommended to avoid mixed format expressions in arithmetic operations.
Operation  Digits Before Decimal Point  Digits After Decimal Point 

Addition/Subtraction  Fi + 1 or Si + 1 (whichever is greater)  Fd or Sd (whichever is greater) 
Multiplication  Fi + Si 

Division  Fi + Sd  (see below) 
Exponentiation  29  Fd (See Exception below)  Fd 
 where:
F  First operand 

S  Second operand 
R  Result 
i  Digits before decimal point 
d  Digits after decimal point 
If the exponent has one or more digits after the decimal point, the exponentiation is internally carried out in floating point format and the result will also have floating point format. See Arithmetic Operations with FloatingPoint Numbers for further information.
The precision of the result of a division depends whether a result field is available or not:
If a result field is available, the precision is: Fd or Rd (whichever is greater) ^{*}.
If no result field is available, the precision is: Fd or Sd (whichever is greater) ^{*}.
^{*} If the ROUNDED
option is used, the precision of the result is
internally increased by one digit before the result is actually rounded.
A result field is available (or assumed to be available) in a COMPUTE
and
DIVIDE
statement, and in a logical condition in which the division is
placed after the comparison operator (for example: IF #A = #B / #C THEN
...
).
A result field is not (or assumed to be not) available in a logical condition in which the
division is placed before the comparison operator (for example: IF #B / #C = #A
THEN ...
).
If both dividend and divisor are of integer format and at least one of them is a
variable, the division result is always of integer format (regardless of the precision
of the result field and of whether the ROUNDED
option is used or not).
The precision of arithmetic expressions, for example: #A / (#B * #C) + #D * (#E 
#F + #G)
, is derived by evaluating the results of the arithmetic operations in
their processing order. For further information on arithmetic expressions, see arithmeticexpression
in the
COMPUTE
statement
description.
In an addition, subtraction, multiplication or division, an error can occur if the total number of digits (before and after the decimal point) of the result is greater than 31.
In an exponentiation, an error occurs in any of the following situations:
if the base is of packed format with precision digits (for example, P3.2) and an exponent greater than 16;
if the base is of floatingpoint format and the result is greater than approximately 7 * 10^{75}.
Generally, the following rules apply:
All scalar operations may be applied to array elements which consist of a single occurrence.
If a variable is defined with a constant value (for example, #FIELD (I2)
CONSTANT <8>
), the value will be assigned to the variable at
compilation, and the variable will be treated as a constant. This means that if such a
variable is used in an array index, the dimension concerned has a definite
number of occurrences.
If an assignment/comparison operation involves two arrays with a different number of dimensions, the "missing" dimension in the array with fewer dimensions is assumed to be (1:1).
Example: If #ARRAY1 (1:2)
is assigned to #ARRAY2 (1:2,1:2)
,
#ARRAY1
is assumed to be #ARRAY1 (1:1,1:2)
.
The following topics are covered below:
The first, second and third dimensions of an array are defined as follows:
Number of Dimensions  Properties 

3  #a3(3rd dim., 2nd dim., 1st dim.) 
2  #a2(2nd dim., 1st dim.) 
1  #a1(1st dim.) 
If an array range is assigned to another array range, the assignment is performed element by element.
Example:
DEFINE DATA LOCAL 1 #ARRAY(I4/1:5) INIT <10,20,30,40,50> ENDDEFINE * MOVE #ARRAY(2:4) TO #ARRAY(3:5) /* is identical to /* MOVE #ARRAY(2) TO #ARRAY(3) /* MOVE #ARRAY(3) TO #ARRAY(4) /* MOVE #ARRAY(4) TO #ARRAY(5) /* /* #ARRAY contains 10,20,20,20,20
If a single occurrence is assigned to an array range, each element of the range is filled with the value of the single occurrence. (For a mathematical function, each element of the range is filled with the result of the function.)
Before an assignment operation is executed, the individual dimensions of the arrays involved are compared with one another to check if they meet one of the conditions listed below. The dimensions are compared independently of one another; that is, the 1st dimension of the one array is compared with the 1st dimension of the other array, the 2nd dimension of the one array is compared with the 2nd dimension of the other array, and the 3rd dimension of the one array is compared with the 3rd dimension of the other array.
The assignment of values from one array to another is only allowed under one of the following conditions:
The number of occurrences is the same for both dimensions compared.
The number of occurrences is indefinite for both dimensions compared.
The dimension that is assigned to another dimension consists of a single occurrence.
The following program shows which array assignment operations are possible.
DEFINE DATA LOCAL 1 A1 (N1/1:8) 1 B1 (N1/1:8) 1 A2 (N1/1:8,1:8) 1 B2 (N1/1:8,1:8) 1 A3 (N1/1:8,1:8,1:8) 1 I (I2) INIT <4> 1 J (I2) INIT <8> 1 K (I2) CONST <8> ENDDEFINE * COMPUTE A1(1:3) = B1(6:8) /* allowed COMPUTE A1(1:I) = B1(1:I) /* allowed COMPUTE A1(*) = B1(1:8) /* allowed COMPUTE A1(2:3) = B1(I:I+1) /* allowed COMPUTE A1(1) = B1(I) /* allowed COMPUTE A1(1:I) = B1(3) /* allowed COMPUTE A1(I:J) = B1(I+2) /* allowed COMPUTE A1(1:I) = B1(5:J) /* allowed COMPUTE A1(1:I) = B1(2) /* allowed COMPUTE A1(1:2) = B1(1:J) /* NOT ALLOWED (NAT0631) COMPUTE A1(*) = B1(1:J) /* NOT ALLOWED (NAT0631) COMPUTE A1(*) = B1(1:K) /* allowed COMPUTE A1(1:J) = B1(1:K) /* NOT ALLOWED (NAT0631) * COMPUTE A1(*) = B2(1,*) /* allowed COMPUTE A1(1:3) = B2(1,I:I+2) /* allowed COMPUTE A1(1:3) = B2(1:3,1) /* NOT ALLOWED (NAT0631) * COMPUTE A2(1,1:3) = B1(6:8) /* allowed COMPUTE A2(*,1:I) = B1(5:J) /* allowed COMPUTE A2(*,1) = B1(*) /* NOT ALLOWED (NAT0631) COMPUTE A2(1:I,1) = B1(1:J) /* NOT ALLOWED (NAT0631) COMPUTE A2(1:I,1:J) = B1(1:J) /* allowed * COMPUTE A2(1,I) = B2(1,1) /* allowed COMPUTE A2(1:I,1) = B2(1:I,2) /* allowed COMPUTE A2(1:2,1:8) = B2(I:I+1,*) /* allowed * COMPUTE A3(1,1,1:I) = B1(1) /* allowed COMPUTE A3(1,1,1:J) = B1(*) /* NOT ALLOWED (NAT0631) COMPUTE A3(1,1,1:I) = B1(1:I) /* allowed COMPUTE A3(1,1:2,1:I) = B2(1,1:I) /* allowed COMPUTE A3(1,1,1:I) = B2(1:2,1:I) /* NOT ALLOWED (NAT0631) END
Generally, the following applies: if arrays with multiple dimensions are compared, the individual dimensions are handled independently of one another; that is, the 1st dimension of the one array is compared with the 1st dimension of the other array, the 2nd dimension of the one array is compared with the 2nd dimension of the other array, and the 3rd dimension of the one array is compared with the 3rd dimension of the other array.
The comparison of two array dimensions is only allowed under one of the following conditions:
The array dimensions compared with one another have the same number of occurrences.
The array dimensions compared with one another have an indefinite number of occurrences.
All array dimensions of one of the arrays involved are single occurrences.
The following program shows which array comparison operations are possible:
DEFINE DATA LOCAL 1 A3 (N1/1:8,1:8,1:8) 1 A2 (N1/1:8,1:8) 1 A1 (N1/1:8) 1 I (I2) INIT <4> 1 J (I2) INIT <8> 1 K (I2) CONST <8> ENDDEFINE * IF A2(1,1) = A1(1) THEN IGNORE ENDIF /* allowed IF A2(1,1) = A1(I) THEN IGNORE ENDIF /* allowed IF A2(1,*) = A1(1) THEN IGNORE ENDIF /* allowed IF A2(1,*) = A1(I) THEN IGNORE ENDIF /* allowed IF A2(1,*) = A1(*) THEN IGNORE ENDIF /* allowed IF A2(1,*) = A1(I 3:I+4) THEN IGNORE ENDIF /* allowed IF A2(1,5:J) = A1(1:I) THEN IGNORE ENDIF /* allowed IF A2(1,*) = A1(1:I) THEN IGNORE ENDIF /* NOT ALLOWED(NAT0629) IF A2(1,*) = A1(1:K) THEN IGNORE ENDIF /* allowed * IF A2(1,1) = A2(1,1) THEN IGNORE ENDIF /* allowed IF A2(1,1) = A2(1,I) THEN IGNORE ENDIF /* allowed IF A2(1,*) = A2(1,1:8) THEN IGNORE ENDIF /* allowed IF A2(1,*) = A2(I,I 3:I+4) THEN IGNORE ENDIF /* allowed IF A2(1,1:I) = A2(1,I+1:J) THEN IGNORE ENDIF /* allowed IF A2(1,1:I) = A2(1,I:I+1) THEN IGNORE ENDIF /* NOT ALLOWED(NAT0629) IF A2(*,1) = A2(1,*) THEN IGNORE ENDIF /* NOT ALLOWED(NAT0629) IF A2(1,1:I) = A1(2,1:K) THEN IGNORE ENDIF /* NOT ALLOWED(NAT0629) * IF A3(1,1,*) = A2(1,*) THEN IGNORE ENDIF /* allowed IF A3(1,1,*) = A2(1,I 3:I+4) THEN IGNORE ENDIF /* allowed IF A3(1,*,I:J) = A2(*,1:I+1) THEN IGNORE ENDIF /* allowed IF A3(1,*,I:J) = A2(*,I:J) THEN IGNORE ENDIF /* allowed END
When you compare two array ranges, note that the following two expressions lead to different results:
#ARRAY1(*) NOT EQUAL #ARRAY2(*) NOT #ARRAY1(*) = #ARRAY2(*)
Example:
IF #ARRAY1(1:2) NOT EQUAL #ARRAY2(1:2)
This is equivalent to:
IF (#ARRAY1(1) NOT EQUAL #ARRAY2(1)) AND (#ARRAY1(2) NOT EQUAL #ARRAY2(2))
Condition A is therefore true if the first occurrence of #ARRAY1
does
not equal the first occurrence of #ARRAY2
and the second occurrence of #ARRAY1
does not equal the second
occurrence of #ARRAY2
.
IF NOT #ARRAY1(1:2) = #ARRAY2(1:2)
This is equivalent to:
IF NOT (#ARRAY1(1)= #ARRAY2(1) AND #ARRAY1(2) = #ARRAY2(2))
This in turn is equivalent to:
IF (#ARRAY1(1) NOT EQUAL #ARRAY2(1)) OR (#ARRAY1(2) NOT EQUAL #ARRAY2(2))
Condition B is therefore true if either the first occurrence of
#ARRAY1
does not equal the first occurrence of #ARRAY2
or the second occurrence of #ARRAY1
does not equal the second
occurrence of #ARRAY2
.
A general rule about arithmetic operations with arrays is that the number of occurrences of the corresponding dimensions must be equal.
The following illustrates this rule:
#c(2:3,2:4) := #a(3:4,1:3) + #b(3:5)
In other words:
Array  Dimension Number  Number of Occurrences  Range 

#c  2nd  2  2:3 
#c  1st  3  2:4 
#a  2nd  2  3:4 
#a  1st  3  1:3 
#b  1st  3  3:5 
The operation is performed element by element.
Note:
An arithmetic operation of a different number of dimensions is allowed.
For the example above, the following operations are executed:
#c(2,2) := #a(3,1) + #b(3) #c(2,3) := #a(3,2) + #b(4) #c(2,4) := #a(3,3) + #b(5) #c(3,2) := #a(4,1) + #b(3) #c(3,3) := #a(4,2) + #b(4) #c(3,4) := #a(4,3) + #b(5)
Below is a list of examples of how array ranges may be used in the following ways in
arithmetic operations (in COMPUTE
, ADD
or MULTIPLY
statements). In the examples 14, the number of
occurrences of the corresponding dimensions must be equal.
range := range + range
The addition is performed element by element.
range := range * range
The multiplication is performed element by element.
range := range + scalar
The scalar is added to each element of the range.
range := range * scalar
Each element of the range is multiplied by the scalar.
scalar := range + scalar
Each element of the range is added to the scalar and the result is assigned to the scalar.
scalar := range * scalar
The scalar is multiplied by each element of the array and the result is assigned to the scalar.
If you use mixed source fields for the operation (range and scalar), the performed action depends on the type of the target field (range or scalar).
There is not specific input sequence, you can use scalar + range and scalar * range and also range + scalar and range * scalar.
Since intermediate results will be generated for arithmetic operations as shown in the above examples, the result of overlapping index ranges is computed element by element in an intermediate result array and finally the intermediate result array is assigned to the result field.
Example:
DEFINE DATA LOCAL 1 #ARRAY(I4/1:5) INIT <10,20,30,40,50> ENDDEFINE #ARRAY(3:5) := #ARRAY(2:4) + 1 /* A temporary array for the /* intermediate result values is /* generated implicitly: #temp(1:3). /* The following operations are /* performed internally: /* #temp(1) := #ARRAY(2) + 1 /* #temp(2) := #ARRAY(3) + 1 /* #temp(3) := #ARRAY(4) + 1 /* #ARRAY(3:5) := #temp(1:3) /* /* #ARRAY contains 10,20,21,31,41