# Chande Momentum Oscillator

## Technical Analysis Indicator: cmo ## Function Prototype

/* Chande Momentum Oscillator */
/* Type: indicator */
/* Input arrays: 1    Options: 1    Output arrays: 1 */
/* Inputs: real */
/* Options: period */
/* Outputs: cmo */
int ti_cmo_start(TI_REAL const *options);
int ti_cmo(int size,
TI_REAL const *const *inputs,
TI_REAL const *options,
TI_REAL *const *outputs);

## Description

This documentation is still a work in progress. It has omissions, and it probably has errors too. If you see any issues, or have any general feedback, please get in touch.

The Chande Momentum Oscillator is a momentum oscillator to help identify trends. It is similar to Relative Strength Index.

It takes one parameter, the period n.

Calculation is as follows:

$$up_{t} = \begin{cases} in_{t} - in_{t-1} & \mathrm{if} \; in_{t} > in_{t-1} \\ 0 & \mathrm{else} \end{cases}$$
$$down_{t} = \begin{cases} in_{t-1} - in_{t} & \mathrm{if} \; in_{t} \lt in_{t-1} \\ 0 & \mathrm{else} \end{cases}$$
$$sup_{t} = \sum_{i = 0}^{n-1} up_{t-i}$$
$$sdown_{t} = \sum_{i = 0}^{n-1} down_{t-i}$$
$$rsi_{t} = 100 \frac{sup_{t} - sdown_{t}}{sup_{t} + sdown_{t}}$$

## Example Usage

### Calling From C

/* Example usage of Chande Momentum Oscillator */
/* Assuming that 'input' is a pre-loaded array of size 'in_size'. */
TI_REAL *inputs[] = {input};
TI_REAL options[] = {5}; /* period */
TI_REAL *outputs; /* cmo */

/* Determine how large the output size is for our options. */
const int out_size = in_size - ti_cmo_start(options);

/* Allocate memory for output. */
outputs = malloc(sizeof(TI_REAL) * out_size); assert(outputs != 0); /* cmo */

/* Run the actual calculation. */
const int ret = ti_cmo(in_size, inputs, options, outputs);
assert(ret == TI_OKAY);


### Calling From Lua (with Tulip Chart bindings)

-- Example usage of Chande Momentum Oscillator
cmo = ti.cmo(input, 5)


## Example Calculation

period = 5

dateinputcmo
2005-11-0181.59
2005-11-0281.06
2005-11-0382.87
2005-11-0483.00
2005-11-0783.61
2005-11-0883.1544.07
2005-11-0982.8453.61
2005-11-1083.9942.11
2005-11-1184.5550.16
2005-11-1484.3628.09
2005-11-1585.5370.41
2005-11-1686.5490.69
2005-11-1786.8988.42
2005-11-1887.7789.44
2005-11-2187.2975.32

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