I am trying to get the Inverse of the GLog function. Is there way to export the formula for this?
I am not aware of such. What I have used in the past, is a little piece of JSL that uses a B Tree Lookup to do close approximations to determine the result.
Here is a little script that creates the will return a untransformed value from a saved transformed formula. Tell me if this is something you think is useful
Names Default to Here( 1 ); dt=open("$SAMPLE_DATA\semiconductor Capability.jmp"); Dis =dt << Distribution(invisible, Continuous Distribution( Column( :NPN1 ), Fit Distribution( GLog( Spec Limits( LSL( 104.412948990151 ), USL( 131.893493064355 ), Target( 118.153221027253 ) ) ) ) ), SendToReport( Dispatch( {"NPN1"}, "Distrib Histogram", FrameBox, {DispatchSeg( LabelSeg( 4 ), {Font( "Arial Unicode MS", 9, "Plain" )} ), DispatchSeg( LabelSeg( 5 ), {Font( "Arial Unicode MS", 9, "Plain" )} ), DispatchSeg( LabelSeg( 6 ), {Font( "Arial Unicode MS", 9, "Plain" )} )} ) ) ); Dis<< Fit Distribution( GLog( Save Transformed ) ); Dis << Delete Window; Wait(0); RawFormula = ""; RawFormula = char(column(N Cols(dt))<<get formula); ColName = "NPN1"; Target = -0.0890560572933256; /***********************************************************************/ /* */ /* The getformula column retrieves the formula from the translation */ /* column and replaces the Original Column name in the formula with */ /* string "__value__". The value of this variable is what will be */ /* evaluated in the successive approximations done by the script. */ /* */ /***********************************************************************/ getformula = Function( {ColName, RawFormula}, TheFormula = uppercase(RawFormula); // Check to see that a formula was found If( Is Empty( TheFormula ) == 1, Dialog( " The column specified as", "the Transformed Column does", " not contain a formula. ", " ", " Please rerun and select", " the correct column" ); Throw(); ); // Get the actual name of the orignal column since // the upper,lower case and spacing is critical in determining // where in the formula the column name actually occurs //ColName = Column( ColName ) << Get Name; // Determine if the reference to the column name in the // formula is a simple :colname reference or a complex // reference :Name(\!"colname\!") // If the column name isn't found set the return code to -1 If( Contains( TheFormula, ":" || ColName ), ColonColName = ":" || ColName// , // Else Contains( TheFormula, ":Name(\!"" || ColName || "\!")" ), ColonColName = ":Name(\!"" || ColName || "\!")"// , // Else rc = -1 ); // Replace all of the column references in the formula with // the string "(__value__)" so that when the formula is // evaluated later, it will take the then value of the memory // variable called __value__ and use it in the formula If( Contains( TheFormula, ColonColName ) > 0, While( Contains( TheFormula, ColonColName ) > 0, TheFormula = Munger( TheFormula, 1, ColonColName, "(__Value__)" ) ), Dialog( " The column specified as", "the Transformed Column does", " not contain a reference", " to the original column.", " in it's formula.", " ", " Please rerun and select", " the correct column" ); Throw(); ); TheFormula; ); /***********************************************************************/ /* */ /* The gettrans function evaluates the formula in the transformed */ /* and converts the formula into a generic form for repeated use in */ /* running of the script. */ /* */ /***********************************************************************/ gettrans = Function( { ColName,RawFormula,TheTarget}, {TheFormula, High, Low, TheTarget, TheMax, Themin, __value__}, TheFormula = getformula(ColName,RawFormula); // The program uses successive approximations to determine the different // parametrics. The way it works is that it calculates the needed parameter // such as Mean, or Standard Deviation, and then by using successive // approximations from the original column's values, and passing those // values through the columns formula, when the approximation value matches // the calculated value from the transformed column, the retransformed value // has been found // Set the extreem valuesH High = 999999999999999999999999; Low = -999999999999999999999999; // Check to see if negative values fail __value__= -1; if(isMissing(try(eval(parse(theformula)),.))==1,Low=0;); // Make a guess at the first value __value__ = Mean( High, Low ); // Iterate the guessing for up to 100 times, adjusting by 1/2 on each loop For( i = 1, i <= 100, i++, TheResult = Eval( Parse( theformula ) ); If( TheResult > TheTarget, High = __value__, TheResult < TheTarget, Low = __value__, Break() ); If( High == Low, Break() ); __value__ = Mean( High, Low ); ); __value__; // Expose the return value ); // End of function gettrans trans=gettrans(ColName,rawformula,Target); show(column(dt,ColName)[1],trans);
