# True Strength Index (TSI)

get_tsi(quotes, lookback_periods=25,smooth_periods=13, signal_periods=7)

## Parameters

name | type | notes |
---|---|---|

`quotes` | Iterable[Quote] | Iterable of the Quote class or its sub-class. • See here for usage with pandas.DataFrame |

`lookback_periods` | int, default 25 | Number of periods (`N` ) for the first EMA. Must be greater than 0. |

`smooth_periods` | int, default 13 | Number of periods (`M` ) for the second smoothing. Must be greater than 0. |

`signal_periods` | int, default 7 | Number of periods (`S` ) in the TSI moving average. Must be greater than or equal to 0. |

### Historical quotes requirements

You must have at least `N+M+100`

periods of `quotes`

to cover the convergence periods. Since this uses a two EMA smoothing techniques, we recommend you use at least `N+M+250`

data points prior to the intended usage date for better precision.

`quotes`

is an `Iterable[Quote]`

collection of historical price quotes. It should have a consistent frequency (day, hour, minute, etc). See the Guide for more information.

## Return

```
TSIResults[TSIResult]
```

- This method returns a time series of all available indicator values for the
`quotes`

provided. `TSIResults`

is just a list of`TSIResult`

.- It always returns the same number of elements as there are in the historical quotes.
- It does not return a single incremental indicator value.
- The first
`N+M-1`

periods will have`None`

values since there’s not enough data to calculate. `signal`

will be`None`

for all periods if`signal_periods=0`

.

⚞

Convergence warning: The first`N+M+250`

periods will have decreasing magnitude, convergence-related precision errors that can be as high as ~5% deviation in indicator values for earlier periods.

### TSIResult

name | type | notes |
---|---|---|

`date` | datetime | Date |

`tsi` | float, Optional | True Strength Index |

`signal` | float, Optional | Signal line (EMA of TSI) |

### Utilities

See Utilities and Helpers for more information.

## Example

```
from stock_indicators import indicators
# This method is NOT a part of the library.
quotes = get_historical_quotes("SPY")
# Calculate 20-period TSI
results = indicators.get_tsi(quotes, 25, 13, 7)
```

## About True Strength Index (TSI)

Created by William Blau, the True Strength Index is a momentum oscillator that depicts trends in price changes. [Discuss] 💬