Add some python examples that can be executed in build

pythondemo/curve1.py

+import swig.pylmfit as pylm
+
+def f(t, p):
+    return p[0] + p[1]*t + p[2]*t**2
+
+def curve1():
+    par0 = pylm.VectorDouble([100, 0, -10])
+    t = pylm.VectorDouble([-4, -3, -2, -1, 0, 1, 2, 3, 4])
+    y = pylm.VectorDouble([16.6, 9.9, 4.4, 1.1, 0, 1.1, 4.2, 9.3, 16.4])
+    control = pylm.lm_control_double
+    pylm.set_parlen(3)
+    pylm.set_callback(f)
+
+    print("Fitting...")
+    result = pylm.fit_curve(par0, t, y, pylm.function_g, control)
+
+    print("Results:")
+    print(f"status after {result.status.nfev} function evaluations:")
+    pylm.print_infmsg(result.status.outcome)
+
+    print("Obtained parameters:")
+    for j in range(pylm.parlen()):
+        print(f"par[{j}] = {result.par[j]}")
+    print("Obtained norm:")
+    print(result.status.fnorm)
+
+    print("fitting data as follows:")
+    for i in range(t.size()):
+        fi = f(t[i], result.par)
+        print(f"t[{i}] = {t[i]}  y = {y[i]}  fit = {fi}  residue = {y[i]-fi}")
+
+    if (result.status.outcome > 3):
+        print("FAILURE")
+        return 1
+    print("SUCCESS")
+    return 0
+
+if __name__ == "__main__":
+    print(curve1())

pythondemo/nonlin1.py

+import swig.pylmfit as pylm
+import sys
+
+def eval_nonlin(p, data=None):
+    f0 = p[0]**2 + p[1]**2 - 1
+    f1 = p[1] - p[0]**2
+    return ([f0, f1], 0)
+
+def nonlin1(p0, p1):
+    par0 = pylm.VectorDouble([p0, p1])
+    control = pylm.lm_control_double
+    pylm.set_parlen(2)
+    pylm.set_callback(eval_nonlin)
+
+    print("Minimization:")
+    result = pylm.minimize(par0, None, 2, pylm.function_eval, control)
+
+    print(f"status after {result.status.nfev} function evaluations:")
+    pylm.print_infmsg(result.status.outcome)
+
+    print("\nSolution:")
+    print(f"  x = {result.par[0]}")
+    print(f"  y = {result.par[1]}")
+    stat_str = "valid, though not the only solution: try other starting values"
+    if (result.status.fnorm >= control.ftol):
+        stat_str = "not a valid solution, try other starting values"
+    print(f"  d = {result.status.fnorm} => {stat_str}")
+
+if __name__ == "__main__":
+    if (len(sys.argv) < 3):
+        print("usage: python nonlin1.py x_start y_start")
+    else:
+        p0 = float(sys.argv[1])
+        p1 = float(sys.argv[2])
+        nonlin1(p0, p1)

pythondemo/surface1.py

+import swig.pylmfit as pylm
+
+class Data_t(object):
+    y: list()
+    tx: list()
+    tz: list()
+    def __init__(self, y, tx, tz):
+        self.y = y
+        self.tx = tx
+        self.tz = tz
+
+    def f(self, tx, tz, p):
+        return p[0] + p[1]*tx + p[2]*tz
+
+def eval_surface(p, data=None):
+    fvec = []
+    for i in range(4):
+        fvec.append(data.y[i] - data.f(data.tx[i], data.tz[i], p))
+    return (fvec, 0)
+
+def surface1():
+    par0 = pylm.VectorDouble([-1, 0, 1])
+    tx = [-1, -1, 1, 1]
+    tz = [-1, 1, -1, 1]
+    y = [0, 1, 1, 2]
+    data = Data_t(y, tx, tz)
+    wrap = pylm.Data_Wrap(data)
+    pylm.set_parlen(3)
+    pylm.set_callback(eval_surface)
+    control = pylm.lm_control_double
+
+    print("Fitting:")
+    result = pylm.minimize(par0, pylm.to_void(wrap), 4, pylm.function_eval, control)
+
+    print("\nResults:")
+    print(f"status after {result.status.nfev} function evaluations:")
+    pylm.print_infmsg(result.status.outcome)
+    print("Obtained parameters:")
+    for j in range(par0.size()):
+        print(f"par[{j}] = {result.par[j]}")
+
+    print("Fitting data as follows:")
+    for i in range(len(tx)):
+        ff = data.f(tx[i], tz[i], result.par)
+        print(f"  t[{i}]={tx[i]},{tz[i]}  y={y[i]} fit={ff} residue={y[i]-ff}")
+
+    if (result.status.fnorm > 1e-14):
+        print(f"FAILURE (obtained norm = {result.status.fnorm} is too large)")
+        return 1
+    print(f"SUCCESS (obtained norm = {result.status.fnorm})")
+    return 0
+
+if __name__ == "__main__":
+    print(surface1())