Entering function parameters manually
Often one may want to enter function parameters manualy so as to obtain initial guess for functions that require them.
By pressing the 
button on the bottom menu bar, test parameters mode is initiated. Parameters for the function selected can be entered. One the parameters have been entered the user has three options:
Cancel - Finished with test parameter mode, keyboard is retracted.
Test - Use the parmeters manual entered for the given function and plot the resulting curve (shown as a dashed line, see right bottom).
Fit - The selected least-squares algorithm is used to fit the data starting with the manually entered parameters and the selected function.
