Revision as of 20:34, 5 October 2007

(stub)

Declaration

StepInterp( D,A,X,I)

Notes

StepInterp uses "right-lookup", finding a value u in D such that x<=u. In the interpolated graph, this makes the the step up takes place at the left edge of each interval. Sometimes you might want a "left-lookup", finding a value u in D such that u<=x. One implementation of this other variant is a UDF:

Function LStepInterp(D:ascending[I] ; R:Array[I] ; X ; I : Index )
Definition: 
   Var pos := StepInterp(D,@I,X,I);
   R[@I= if X=D[@I=pos] then pos else max([1,pos-1]) ]

@@ Line 10: / Line 10: @@
 = Notes =
-StepInterp uses a "left-step" -- the step up takes place at the left side of each interval.  Sometimes you might want a "right-step", using the previous value smaller than or equal to X, rather than the next value greater than or equal to X.  One implementation of this other variant is a [[User-Defined Functions|UDF]]:
+StepInterp uses "right-lookup", finding a value u in D such that x<=u.  In the interpolated graph, this makes the the step up takes place at the left edge of each interval.  Sometimes you might want a "left-lookup", finding a value u in D such that u<=x.  One implementation of this other variant is a [[User-Defined Functions|UDF]]:
-  Function RStepInterp(D:ascending[I] ; R:Array[I] ; X ; I : Index )
+  Function LStepInterp(D:ascending[I] ; R:Array[I] ; X ; I : Index )
   Definition:
      Var pos := StepInterp(D,@I,X,I);

Difference between revisions of "StepInterp"

Revision as of 20:34, 5 October 2007

Declaration

Notes

See Also