On 10/12/06, Greg Willden <[EMAIL PROTECTED]> wrote: > On 10/11/06, Travis Oliphant <[EMAIL PROTECTED]> wrote: > > Stefan van der Walt wrote: > > >Further, if I understand correctly, changing sqrt and power to give > > >the right answer by default will slow things down somewhat. But is it > > >worth sacrificing intuitive usage for speed? > > > > > For NumPy, yes. > > > > This is one reason that NumPy by itself is not a MATLAB replacement. > > This is not about being a Matlab replacement. > This is about correctness. > Numpy purports to handle complex numbers. > Mathematically, sqrt(-1) is a complex number. > Therefore Numpy *must* return a complex number. > Speed should not take precedence over correctness.
Unless your goal is speed. Then speed should take precedence over correctness. And unless you're a fan of quaternions, in which case *which* square root of -1 should it return? It's interesting to note that although python has had complex numbers pretty much from the beginning, math.sqrt(-1) returns an error. If you want to work with complex square roots you need to use cmath.sqrt(). Basically you have to tell python that compex numbers are something you care about by using the module designed for complex math. This scimath module is a similar deal. But perhaps the name could be a little more obvious / short? Right now it seems it only deals with complex numbers, so maybe having "complex" or "cmath" in the name would make it clearer. Hmm there is a numpy.math, why not a numpy.cmath. > If Numpy doesn't return a complex number then it shouldn't pretend to > support complex numbers. That's certainly being overdramatic. Lot's of folks are doing nifty stuff with complex FFTs every day using numpy/scipy. And I'm sure they will continue to no matter what numpy.sqrt(-1) returns. --bb ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion