Last modified: December 2018

URL: http://cxc.harvard.edu/sherpa/ahelp/log.html
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AHELP for CIAO 4.11 Sherpa v1

log

Context: models

Synopsis

One-dimensional natural logarithm function.

Syntax

log

Example

>>> create_model_component("log", "mdl")
>>> print(mdl)

Create a component of the log model and display its default parameters. The output is:

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.offset   thawed            0 -3.40282e+38  3.40282e+38           
   mdl.coeff    thawed           -1 -3.40282e+38  3.40282e+38           
   mdl.ampl     thawed            1            0  3.40282e+38           

ATTRIBUTES

The attributes for this object are:

offset

The offset of the model.

coeff

The scaling factor.

ampl

The amplitude of the model.

Notes

The functional form of the model for points is:

f(x) = ampl * log (coeff * (x - offset))

and for an integrated grid it is the integral of this over the bin.


Bugs

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

models
exp, exp10, log10, logparabola, sqrt