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### Vector Operations

SIC supports array variables of up to 4 dimensions. Array dimensions are specified between brackets (not parentheses) with the comma as separators. CHARACTER and LOGICAL variables can also be arrays. Arithmetic operations always work on arrays on an element by element basis. Scalar variables are considered like arrays of any size. For example,

DEFINE REAL A[5] B[5]
LET A = ABS(B)
LET B = 1.0
assigns to each element of A the absolute value of the corresponding element of B, and then assigns to each element of B the value 1.0. Dimensions of arrays must match in arithmetic expressions.

Any subset of an array variable can be referenced in an expression, for example

DEFINE REAL A[5] B[5,10] C[5,10,3]
LET B[,6] = A
LET C[,10,1] = B[,3]
Dimensions of the sub-arrays must also match. Transposition is now supported : e.g. in the precedent example, C[1,,1] could have replaced C[,10,1]. The indices can be previously defined scalar variables. Leading commas may be omitted.
DEFINE REAL A[5] B[5,10] C[5,10,3]
LET B[,6] = A
LET C[,10,1] = B[,3]

It is also possible to specify a range of indexes rather than a single index.

DEFINE REAL A[5] B[3,10] C[4,4,4]
LET B[,6] = A[2:4]
LET A[:3] = B[,8]
LET A[2:5] = C[3,,4]

Gildas manager 2014-07-01