Script to print the per-timestep interpolated error plus maximum

and average error when comparing client and server debug output.

tools/compute_client_error.py

@@ -0,0 +1,92 @@
+#!/usr/bin/env python
+
+import math
+import sys
+
+def usage():
+    print "Usage:"
+    print "compute_client_error.py server-data[,time,x,z] client-data[time,x,z]"
+    print "The files are expected to contain space separated fields. The"
+    print "option time,x,z specification is the field number of the STK world"
+    print "time, x and z coordinate."
+    print "The location of the kart in each field are specified by the"
+    print "field attribute. It is the field number (space separated fields)"
+    print "of the x coordinate, with the z coordinate being field+2"
+    print "It computes for each data point in the client file the closest"
+    print "the two data points with the closest time stamp in the server"
+    print "and then interpolates the server position based on the client"
+    print "time between these positions. The difference between the"
+    print "intepolated position"
+
+    sys.exit()
+
+# -----------------------------------------------------------------------------
+def splitArg(s):
+    l = s.split()
+    if len(l)==1:
+        return s,5,8,10   # Default for current debug output
+    if len(l)!=4:
+        print "Incorrect specification: '%s'"%s
+        usage()
+    return l[0], int(l[1]), int(l[2]), int(l[3])
+# -----------------------------------------------------------------------------
+def readFile(name, time, x, z):
+    f = open(name, "r")
+    result = []
+    for i in f.readlines():
+        if i[:6] == "Rewind":
+            continue
+        l = i.split()
+        result.append( (float(l[time]),
+                        float(l[x]   ),
+                        float(l[z]   ) ) )
+    f.close()
+    return result
+        
+# -----------------------------------------------------------------------------
+# Compares the client and server data. Each argument is a list of
+# triplets containing (time, x, z) data.
+#
+def computeDifferences(server, client):
+    index_s = 0
+
+    count = 0
+    sum   = 0.0
+    min   = 999999.9
+    max   = -1.0
+    for (time, x, z) in client:
+        # Find largest entry in server data that is <= client's time:
+        while index_s<len(server)-2:
+            t1 = server[index_s+1][0]
+            if t1>time: break
+            index_s += 1
+
+        #print "time", time, server[index_s][0], server[index_s+1][0]
+
+        t1,x1,z1 = server[index_s  ]
+        t2,x2,z2 = server[index_s+1]
+        f = (time-t1)/(t2-t1)
+        x_i = x1 + f * (x2-x1)
+        z_i = z1 + f * (z2-z1)
+        error = math.sqrt((x-x_i)**2 + (z-z_i)**2)
+        #print t1,x1,t2,x2,time,x_i
+        print time, error
+        if (error < min): min=error
+        if (error > max): max=error
+        count += 1
+        sum += error
+
+    print "sum %f count %d min %f average %f max %f" \
+        % (sum, count, min, sum/count, max)
+# -----------------------------------------------------------------------------
+
+if __name__=="__main__":
+    if len(sys.argv)!=3:
+        usage()
+    server_name, time_s, x_s, z_s = splitArg(sys.argv[1])
+    client_name, time_c, x_c, z_c = splitArg(sys.argv[2])
+
+    server = readFile(server_name, time_s, x_s, z_s)
+    client = readFile(client_name, time_c, x_c, z_c)
+    
+    computeDifferences(server, client)