tweak

tweak helps visually evaluate the effect of changing or tweaking a parameter in an expression containing a function which can produce a 2D plot. It then creates a slider for each parameter that needs tweaking. E.g. 'a*sin(b*x+c); would be the first argument, and its parameters ('a', 'b' or 'c') the second. An adjustment range for a given parameter can be specified as the third argument.
Examples
x = linspace(0,1,1000); a = 2; b = 10; c = 100;
tweak('a*sin(x*b+c)', 'b') ;
tweak('a*sin(x*b+c)', 'a', [0.1, 2]);
Here, the the first invocation of tweak will allow the adjustment of b by +/- 0.5*b around it's value by opening a plot of the expression and creating a slider for the parameter 'b' that allows values from 5 to 15 (i.e. 10 +/- 5) and from 0.1 to 2 for 'a' respectively. Note, that if the plot remains open after the first tweak, a second slider (for 'a') will be simply added to the figure, so that the two parameters can be tweaked interchangeably.
The values of the parameters in the main workspace will be set by the final positions of the corresponding sliders.