15.5.532 scb

scb, x, s, c [, /even, /odd]

Sine-cosine inverse transform (in the first dimension) to x. s and c must contain the sine and cosine coefficients, respectively, as returned by sc: element i corresponds to wavelength num_elem(x)/i.

Because of the way the sine and cosine transform values are stored, it is not possible to unambiguously determine the number of data elements that x should get. If the first dimension of the sine and cosine transforms contains n elements, then these might have come from an x with 2*n or 2*n + 1 elements in the first dimension. If the highest-frequency sine value(s) is/are equal to zero, then it is likely that the results derive from transforms involving an even number of data points, though the zero(s) may also be due to an odd number of very fortuitous data values.

To resolve this difficulty, the following rules are followed: If /even is specified, then assume n is even. If /odd is specified, then assume n is odd. If neither /even nor /odd are specified, then inspect the highest-frequency sine transform (s) values: if all of them are equal to zero, then assume n is even, otherwise odd.

Reverse: sc

See also: power, fft, hilbert