tools/footprint/linear-regression.awk

   1 # This Source Code Form is subject to the terms of the Mozilla Public
   2 # License, v. 2.0. If a copy of the MPL was not distributed with this
   3 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
   4
   5 function regress(DATAPOINTS,SX,SY,SXY,SX2)
   6 {
   7    b1 = (DATAPOINTS * SXY - SX * SY) / (DATAPOINTS * SX2 - SX * SX);
   8    b0 = (SY - b1 * SX ) / DATAPOINTS;
   9    return b1 " * x + " b0;
  10 }
  11
  12 BEGIN {
  13         if (!Skip) Skip = 0;
  14         if (Interval)
  15         {
  16            Count = 0;
  17            IntervalCount = 0;
  18         }
  19       }
  20
  21 NR>Skip {
  22         sx += $1;
  23         sy += $2;
  24         sxy += $1 * $2;
  25         sx2 += $1 * $1;
  26         #print NR " " sx " " sy " " sxy " " sx2
  27
  28         if (Interval)
  29         {
  30            if(Count == Interval-1)
  31            {
  32               IntervalCount += 1;
  33
  34               print NR-Count, "-", NR, ":  ", regress(Count,isx,isy,isxy,isx2);
  35
  36               Count = 0;
  37               isx = 0;
  38               isy = 0;
  39               isxy = 0;
  40               isx2 = 0;
  41            }
  42            else
  43            {
  44               Count += 1;
  45               isx += $1;
  46               isy += $2;
  47               isxy += $1 * $2;
  48               isx2 += $1 * $1;
  49            }
  50         }
  51      }
  52
  53 END {
  54        if(Interval) {
  55           print NR-Count, "-", NR, ":  ", regress(Count,isx,isy,isxy,isx2);
  56        }
  57        print regress(NR-Skip, sx, sy, sxy, sx2);
  58     }