# naginterfaces.library.blas.zcsg¶

naginterfaces.library.blas.zcsg(t)[source]

zcsg reconstructs the parameters (real) and (complex) of a complex plane rotation from the tangent of that rotation.

For full information please refer to the NAG Library document for f06cc

https://www.nag.com/numeric/nl/nagdoc_28.7/flhtml/f06/f06ccf.html

Parameters
tcomplex

The value , the tangent of the rotation.

Returns
cfloat

The value , the cosine of the rotation.

scomplex

The value , the sine of the rotation.

Notes

No equivalent traditional C interface for this routine exists in the NAG Library.

zcsg reconstructs the parameters (real) and (complex) of a complex plane rotation, from the value of the tangent , as returned by zrotgc():

so that is always real and non-negative.

If , where is the machine precision, the function sets and .