/// <summary>
/// Checks whether the parameters are within the feasible range of the problem.
/// </summary>
/// <param name="problem"><see cref="Problem"/>.</param>
/// <param name="parameter"><see cref="Parameter"/>.</param>
/// <returns>It returns null if the parameters are feasible, otherwise an error message is returned.</returns>
public static string CheckParameter(Problem problem, Parameter parameter)
{
if (problem == null)
{
throw new ArgumentNullException(nameof(problem));
}
if (parameter == null)
{
throw new ArgumentNullException(nameof(parameter));
}
problem.ThrowIfDisposed();
unsafe
{
var param = new NativeMethods.svm_parameter();
try
{
// This method throw exception when there is some errors.
// This error check is not official's.
param = parameter.ToNative();
}
catch (LibSvmException lle)
{
return(lle.Message);
}
try
{
var ret = NativeMethods.svm_check_parameter((NativeMethods.svm_problem *)problem.NativePtr, ¶m);
return(Marshal.PtrToStringAnsi(ret));
}
finally
{
Free(¶m);
}
}
}
private static unsafe NativeMethods.svm_parameter ToNative(this Parameter parameter)
{
var ret = new NativeMethods.svm_parameter
{
svm_type = (int)parameter.SvmType,
kernel_type = (int)parameter.KernelType,
degree = parameter.Degree,
gamma = parameter.Gamma,
coef0 = parameter.Coef0,
cache_size = parameter.CacheSize,
eps = parameter.Epsilon,
C = parameter.C,
nr_weight = parameter.LengthOfWeight,
nu = parameter.Nu,
p = parameter.P,
shrinking = parameter.Shrinking ? NativeMethods.True : NativeMethods.False,
probability = parameter.Probability ? NativeMethods.True : NativeMethods.False
};
if (ret.nr_weight > 0)
{
if (parameter.WeightLabel == null)
{
throw new LibSvmException("Parameter.WeightLabel is null although Parameter.LengthOfWeight is over 0.");
}
if (parameter.Weight == null)
{
throw new LibSvmException("Parameter.Weight is null although Parameter.LengthOfWeight is over 0.");
}
var len1 = parameter.WeightLabel.Length;
var len2 = parameter.Weight.Length;
if (len1 != ret.nr_weight || len2 != ret.nr_weight)
{
throw new LibSvmException("Parameter.WeightLabel.Length does not match Parameter.Weight.Length");
}
}
var failAlloc = false;
try
{
if (ret.nr_weight > 0)
{
ret.weight_label = (int *)NativeMethods.malloc(sizeof(int), ret.nr_weight);
fixed(int *p = ¶meter.WeightLabel[0])
NativeMethods.memcpy(ret.weight_label, p, ret.nr_weight * sizeof(int));
ret.weight = (double *)NativeMethods.malloc(sizeof(double), ret.nr_weight);
fixed(double *p = ¶meter.Weight[0])
NativeMethods.memcpy(ret.weight, p, ret.nr_weight * sizeof(double));
}
failAlloc = true;
}
finally
{
if (!failAlloc)
{
NativeMethods.free((IntPtr)ret.weight_label);
NativeMethods.free((IntPtr)ret.weight);
}
}
return(ret);
}
