CMSIS DSP example needed.

Are there any interpolation examples in CMSIS DSP library using cubic spline?

I have a simple waveform where x is the time stamp and y is the sine wave, I can use use MATLAB to plot the

sine wave correctly. I am pretty confident that I parse the same raw data into X and Y data buffer correctly as meas_X and meas_Y.

float outX[2*SAMPLE_LENGTH];

float outY[2*SAMPLE_LENGTH];

float outbuf[2*SAMPLE_LENGTH-1];

float coef[3*(SAMPLE_LENGTH-1)];

arm_spline_instance_f32 S; 

arm_spline_init_f32(&S, ARM_SPLINE_PARABOLIC_RUNOUT, meas_X, meas_Y, SAMPLE_LENGTH, coef, outbuf);
arm_spline_f32(&S, outX, outY, 4);

The outY is always a flat line. Are there any known issues in arm_spline_f32() or something I should be aware of?

Thanks,

Tom