Adding Vectors Containing NANs
QUESTION: I have two vectors (vec1 and vec2). Some of the values of vec1 are set as NaN (not-a-number). I want to sum each point of vec1 with its correspondent point in vec2, ignoring NaN. For example, I define my vectors like this.
vec1 = FltArr(5) + 1 vec1 = !Values.F_NAN vec2 = FltArr(5) + 1 Print, vec1 1.00000 1.00000 NaN 1.00000 1.00000 Print, vec2 1.00000 1.00000 1.00000 1.00000 1.00000
If I try this:
new_vec=vec1+vec2 Print, new_vec 2.00000 2.00000 NaN 2.00000 2.00000
I have NaN's in new_vec which correspond to the NANs in vec1.
If I use Total, IDL tells me that vec2 should be a scalar in this context.
new_vec = Total(vec1, vec2, /NAN) % TOTAL: Expression must be a scalar or 1 element array in this context: VEC2. % Execution halted at: $MAIN$
Is there any other way to ignore the NaN's?
ANSWER: This answer is supplied by Klaus Scipal (email@example.com).
You were right to think of Total, but you are using it incorrectly. The correct syntax is like this.
new_vec = [[vec1],[vec2]] new_vec = Total(new_vec, 2, /NAN) Print, new_vec 2.00000 2.00000 1.00000 2.00000 2.00000
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Last Updated 3 January 2003