Created shaft wizard (moved here from PartDesign branch)

src/Mod/PartDesign/WizardShaft/SegmentFunction.py

@@ -0,0 +1,152 @@
+#/******************************************************************************
+# *   Copyright (c)2012 Jan Rheinlaender <jrheinlaender@users.sourceforge.net> *
+# *                                                                            *
+# *   This file is part of the FreeCAD CAx development system.                 *
+# *                                                                            *
+# *   This library is free software; you can redistribute it and/or            *
+# *   modify it under the terms of the GNU Library General Public              *
+# *   License as published by the Free Software Foundation; either             *
+# *   version 2 of the License, or (at your option) any later version.         *
+# *                                                                            *
+# *   This library  is distributed in the hope that it will be useful,         *
+# *   but WITHOUT ANY WARRANTY; without even the implied warranty of           *
+# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            *
+# *   GNU Library General Public License for more details.                     *
+# *                                                                            *
+# *   You should have received a copy of the GNU Library General Public        *
+# *   License along with this library; see the file COPYING.LIB. If not,       *
+# *   write to the Free Software Foundation, Inc., 59 Temple Place,            *
+# *   Suite 330, Boston, MA  02111-1307, USA                                   *
+# *                                                                            *
+# ******************************************************************************/
+
+class SegmentFunctionSegment:
+    "One segment of a segment function"
+    start = 0
+    variable = "x"
+    coefficient = 0
+    exponent = 0
+
+    def __init__(self, st, var, coeff, exp):
+        self.start = st
+        self.variable = var
+        self.coefficient = coeff
+        self.exponent = exp
+
+    def hasStart(self, xval):
+        "Return true if the start of this segment is xval"
+        #FIXME: 1E-9 is arbitrary here. But since units are in meters, 1E-9 is a nanometer...
+        return abs(self.start - xval) < 1E-9
+
+    def value(self, xval):
+        if xval < self.start:
+            return 0
+        else:
+            return self.coefficient * pow(xval - self.start, self.exponent)
+
+    def clone(self):
+        return SegmentFunctionSegment(self.start, self.variable, self.coefficient, self.exponent)
+
+    def negate(self):
+        self.coefficient *= -1
+
+    def integrate(self):
+        self.exponent = self.exponent + 1
+        self.coefficient = self.coefficient * 1 / self.exponent
+
+    def asString(self):
+        return "%f * {%s - %f}^%i" % (self.coefficient, self.variable, self.start, self.exponent)
+
+class SegmentFunction:
+    "Function that is defined segment-wise"
+    variable = "x"
+    segments = []
+    name = "f(x)"
+
+    def __init__(self, name = "f(x)"):
+        self.variable = "x"
+        self.segments = []
+        self.name = name
+
+    def negate(self):
+        for s in self.segments:
+            s.negate()
+        return self
+
+    def index(self, xval):
+        "Find insert position for start value xval"
+        lastStart = 0.0
+        for i in range(len(self.segments)):
+            newStart = self.segments[i].start
+            if (xval >= lastStart) and (xval < newStart):
+                return i
+            lastStart = newStart
+        return len(self.segments)
+
+    def buildFromDict(self, var, dict):
+        self.variable = var
+        for key in sorted(dict.iterkeys()):
+            #if abs(dict[key]) > 1E-9:
+            self.segments.append(SegmentFunctionSegment(key, var, dict[key], 0))
+
+    def addSegments(self, dict):
+        for key in sorted(dict.iterkeys()):
+            if abs(dict[key]) > 1E-9:
+                self.segments.insert(self.index(key), SegmentFunctionSegment(key, self.variable, dict[key], 0))
+
+    def setMaxX(self, mx):
+        self.maxX = mx
+
+    def value(self, xval):
+        "Return the value of the function at the specified x value"
+        result = 0
+        for s in self.segments:
+            result = result + s.value(xval)
+        return result
+
+    def lowervalue(self, xval):
+        "Return the value of the previous segment at the specified x value"
+        result = 0
+        for s in self.segments:
+            result = result + s.value(xval - 1E-8)
+        return result
+
+    def clone(self):
+        result = SegmentFunction()
+        result.variable = self.variable
+        for s in self.segments:
+            result.segments.append(s.clone())
+        return result
+
+    def integrate(self):
+        "Integrate all segments with respect to the variable"
+        for s in self.segments:
+            s.integrate()
+
+    def integrated(self):
+        "Return a copy of self integrated with respect to the variable"
+        result = self.clone()
+        result.integrate()
+        return result
+
+    def evaluate(self, maxX, pointsX):
+        # Note: This usually creates a few more points than specified in pointsX
+        offset = (maxX - self.segments[0].start) / (pointsX - 1)
+        xvals = set([self.segments[0].start + s * offset for s in range(pointsX)])
+        starts = set([self.segments[i].start for i in range(len(self.segments))])
+        xvals = xvals.union(starts) # Make sure we have a point on each segment start
+        result = []
+        for xval in sorted(xvals):
+            if xval in starts:
+                result.append( (xval, self.lowervalue(xval)) ) # create double point at segment border
+            result.append( (xval, self.value(xval)) )
+        return result
+
+    def output(self):
+        print self.name, " = ",
+        for i in range(len(self.segments)):
+            print self.segments[i].asString(),
+            if i < len(self.segments) - 1:
+                print " + ",
+        print ""
+