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How to produce a log based range variable or plot equation with vector as independent variable?

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How to produce a log based range variable or plot equation with vector as independent variable?

Hello, 

I am working on a project, but can not find a way to produce a decent log plot over a large range. The issue is that if I use the log function under plots with a range variable for my x values there will be too few data points on the low end of the plot to look smooth. So I tried making a log-based x set of data using a range variable converted to a power based set of vector data, variable d, but the when plotting it says can not divide by zero. Though after multiple checks, I do not believe my d values ever goes to zero. I just need to be able to make a plot of y vs log(x) able to span a range of 10^-10 to 10^-3 meters and have sufficient data points for the small x values. 

Also getting this error now for the second attempt, Plotting failed. Replace complex values and NaNs by real numbers.

problem.PNGProblems.PNG 

 

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1 ACCEPTED SOLUTION

Accepted Solutions

Re: How to produce a log based range variable or plot equation with vector as independent variable?

Use the function logspace(min,max,npts) which creates a vector of values from min to max with npts point over the entire range.

Example (to get 5 points per decade):

LM_20171108_logspace.png

 

Success!
Luc

5 REPLIES

Re: How to produce a log based range variable or plot equation with vector as independent variable?

I usually create a range variable,  i := 3, 3.3 . .8

then plot 10^i

Re: How to produce a log based range variable or plot equation with vector as independent variable?

Use the function logspace(min,max,npts) which creates a vector of values from min to max with npts point over the entire range.

Example (to get 5 points per decade):

LM_20171108_logspace.png

 

Success!
Luc

Re: How to produce a log based range variable or plot equation with vector as independent variable?

Ok, will try this.

Re: How to produce a log based range variable or plot equation with vector as independent variable?

Is there a way to add units. Can not seem to get units into the logspace values? If I put them in just ignores them on the output.

Re: How to produce a log based range variable or plot equation with vector as independent variable?

Oh, putting it on the outside of the parentheses works. Thanks again!