IVF and MATHERRQQ

[phil31]

Hi all,

In most of the projects I manage, I have used until now the feature of the MATHERRQQ routine to catch and handle properly math exceptions (I code my own MATHERRQQ routine). Unfortunately this feature is no more available with IVF. (in particular the MTH$E_INFO record that contain information does not exists anymore)

How can I do now ?

In particular, can the SIGNALQQ routine, associated withe the SIG$FPE signal, be used to produce the same behavior if the handler routine is a copy of my "old" MATHERRQQ routine (remaned of course) ?

Thanks.

[Xj_Kong]

Agree to retrieve MATHERRQQ! This made me quite often jump back to CVF.

[Steven_L_Intel1]

Sorry, but we're using a very different math library now. What sort of errors are you hoping to catch and what do you want to do with them?

[Xj_Kong]

Most common is the power, exponential and log functions for instance when the number goes to very large or small sometimes, like type*,(-0.008)**(0.33333333333d0)  as I remember but (-0.008)**(1d0/3d0) works.

Let me keep more report later. 

[Xj_Kong]

The most common cases I met are the power, exponential and log functions for instance when the number goes to very large or small sometimes, like type*,(-0.008)**(0.33333333333d0)  as I remember but (-0.008)**(1d0/3d0) works.

Let me keep more report later. 

[mecej4]

For the example you gave, the issue is not related to the presence of very large or very small numbers.

Here is a point to ponder, from a mathematical point of view. The number -0.008, raised to the 1/3-rd power, is -0.2; however, if the exponent is not exactly 1/3, but the reciprocal of any real number greater than 1, the result is, in general, complex and multiple-valued. The exponent that you gave in the first expression is not exactly equal 1/3. Maple gives, for that expression, the value .1000000000+.1732050808*I, which is close to (1 + i.sqrt(3))/10. Would you accept this result?