33 lines
838 B
Matlab
33 lines
838 B
Matlab
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function i = iota(n, idx)
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% Returns a selection vector.
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%
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% INPUTS
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% - n [integer] scalar, dimension of the returned vector.
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% - idx [integer] vector or scalar, non zero entries indices in the returned vector.
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%
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% OUTPUTS
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% - i [integer] n*1 vector. All elements are zero except those specified in idx.
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if ~isscalar(n) || ~isvector(idx)
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error('First input has to be a scalar and second input a vector!')
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end
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if (n-round(n))>eps(0) || any((idx-round(idx))>eps(0))
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error('Inputs must have integer values!')
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end
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if n<1
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error('First input argument must be a strictly positive integer!')
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end
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if any(idx>n)
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error('Elements in second argument cannot be greater than the first argument!')
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end
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if any(idx<1)
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error('Elements in the second argument must be positive!')
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end
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i = zeros(n, 1);
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i(idx) = 1;
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