Find intersection points for two stock timeseries

Question

Background

I am trying to find intersection points of two series. In this stock example, I would like to find the intersection points of SMA20 & SMA50. Simple Moving Average (SMA) is commonly used as stock indicators, combined with intersections and other strategies will help one to make decision. Below is the code example.

Code

You can run the following with jupyter.

import pandas as pd
import matplotlib.pyplot as plt

%matplotlib inline

datafile = 'output_XAG_D1_20200101_to_20200601.csv'
#This creates a dataframe from the CSV file:
data = pd.read_csv(datafile, index_col = 'Date')

#This selects the 'Adj Close' column
close = data['BidClose']
#This converts the date strings in the index into pandas datetime format:
close.index = pd.to_datetime(close.index)
close

sma20 = close.rolling(window=20).mean()
sma50 = close.rolling(window=50).mean()

priceSma_df = pd.DataFrame({
      'BidClose' : close,
      'SMA 20' : sma20,
      'SMA 50' : sma50
     })

priceSma_df.plot()
plt.show()

Sample Data

This is the data file used in example output_XAG_D1_20200101_to_20200601.csv

Date,BidOpen,BidHigh,BidLow,BidClose,AskOpen,AskHigh,AskLow,AskClose,Volume
01.01.2020 22:00:00,1520.15,1531.26,1518.35,1527.78,1520.65,1531.75,1518.73,1531.73,205667
01.02.2020 22:00:00,1527.78,1553.43,1526.72,1551.06,1531.73,1553.77,1528.17,1551.53,457713
01.05.2020 22:00:00,1551.06,1588.16,1551.06,1564.4,1551.53,1590.51,1551.53,1568.32,540496
01.06.2020 22:00:00,1564.4,1577.18,1555.2,1571.62,1568.32,1577.59,1555.54,1575.56,466430
01.07.2020 22:00:00,1571.62,1611.27,1552.13,1554.79,1575.56,1611.74,1552.48,1558.72,987671
01.08.2020 22:00:00,1554.79,1561.24,1540.08,1549.78,1558.72,1561.58,1540.5,1553.73,473799
01.09.2020 22:00:00,1549.78,1563.0,1545.62,1562.44,1553.73,1563.41,1545.96,1562.95,362002
01.12.2020 22:00:00,1562.44,1562.44,1545.38,1545.46,1562.95,1563.06,1546.71,1549.25,280809
01.13.2020 22:00:00,1545.46,1548.77,1535.78,1545.1,1549.25,1549.25,1536.19,1548.87,378200
01.14.2020 22:00:00,1545.1,1558.04,1543.79,1554.89,1548.87,1558.83,1546.31,1558.75,309719
01.15.2020 22:00:00,1554.89,1557.98,1547.91,1551.18,1558.75,1558.75,1548.24,1554.91,253944
01.16.2020 22:00:00,1551.18,1561.12,1549.28,1556.68,1554.91,1561.55,1549.59,1557.15,239186
01.19.2020 22:00:00,1556.68,1562.69,1556.25,1560.77,1557.15,1562.97,1556.61,1561.17,92020
01.20.2020 22:00:00,1560.77,1568.49,1546.21,1556.8,1561.17,1568.87,1546.56,1558.5,364753
01.21.2020 22:00:00,1556.8,1559.18,1550.07,1558.59,1558.5,1559.47,1550.42,1559.31,238468
01.22.2020 22:00:00,1558.59,1567.83,1551.8,1562.45,1559.31,1568.16,1552.11,1564.17,365518
01.23.2020 22:00:00,1562.45,1575.77,1556.44,1570.39,1564.17,1576.12,1556.76,1570.87,368529
01.26.2020 22:00:00,1570.39,1588.41,1570.39,1580.51,1570.87,1588.97,1570.87,1582.33,510524
01.27.2020 22:00:00,1580.51,1582.93,1565.31,1567.15,1582.33,1583.3,1565.79,1570.62,384205
01.28.2020 22:00:00,1567.15,1577.93,1563.27,1576.7,1570.62,1578.22,1563.61,1577.25,328766
01.29.2020 22:00:00,1576.7,1585.87,1572.19,1573.23,1577.25,1586.18,1572.44,1575.33,522371
01.30.2020 22:00:00,1573.23,1589.98,1570.82,1589.75,1575.33,1590.37,1571.14,1590.31,482710
02.02.2020 22:00:00,1589.75,1593.09,1568.65,1575.62,1590.31,1595.82,1569.85,1578.35,488585
02.03.2020 22:00:00,1575.62,1579.56,1548.95,1552.55,1578.35,1579.87,1549.31,1556.4,393037
02.04.2020 22:00:00,1552.55,1562.3,1547.34,1554.62,1556.4,1562.64,1547.72,1556.42,473172
02.05.2020 22:00:00,1554.62,1568.14,1552.39,1565.08,1556.42,1568.51,1552.73,1567.0,365580
02.06.2020 22:00:00,1565.08,1574.02,1559.82,1570.11,1567.0,1574.33,1560.7,1570.55,424269
02.09.2020 22:00:00,1570.11,1576.9,1567.9,1571.05,1570.55,1577.25,1568.21,1573.34,326606
02.10.2020 22:00:00,1571.05,1573.92,1561.92,1566.12,1573.34,1574.27,1562.24,1568.12,310037
02.11.2020 22:00:00,1566.12,1570.39,1561.45,1564.26,1568.12,1570.71,1561.91,1567.02,269032
02.12.2020 22:00:00,1564.26,1578.24,1564.26,1574.5,1567.02,1578.52,1565.81,1576.63,368438
02.13.2020 22:00:00,1574.5,1584.87,1572.44,1584.49,1576.63,1585.29,1573.28,1584.91,250788
02.16.2020 22:00:00,1584.49,1584.49,1578.7,1580.79,1584.91,1584.91,1579.06,1581.31,101499
02.17.2020 22:00:00,1580.79,1604.97,1580.79,1601.06,1581.31,1605.33,1581.31,1603.08,321542
02.18.2020 22:00:00,1601.06,1612.83,1599.41,1611.27,1603.08,1613.4,1599.77,1613.34,357488
02.19.2020 22:00:00,1611.27,1623.62,1603.74,1618.48,1613.34,1623.98,1604.12,1621.27,535148
02.20.2020 22:00:00,1618.48,1649.26,1618.48,1643.42,1621.27,1649.52,1619.19,1643.87,590262
02.23.2020 22:00:00,1643.42,1689.22,1643.42,1658.62,1643.87,1689.55,1643.87,1659.07,1016570
02.24.2020 22:00:00,1658.62,1660.76,1624.9,1633.19,1659.07,1661.52,1625.5,1636.23,1222774
02.25.2020 22:00:00,1633.19,1654.88,1624.74,1640.4,1636.23,1655.23,1625.11,1642.59,1004692
02.26.2020 22:00:00,1640.4,1660.3,1635.15,1643.99,1642.59,1660.6,1635.6,1646.42,1084115
02.27.2020 22:00:00,1643.99,1649.39,1562.74,1584.95,1646.42,1649.84,1563.22,1585.58,1174015
03.01.2020 22:00:00,1584.95,1610.94,1575.29,1586.55,1585.58,1611.26,1575.88,1590.33,1115889
03.02.2020 22:00:00,1586.55,1649.16,1586.55,1640.19,1590.33,1649.6,1589.43,1644.16,889364
03.03.2020 22:00:00,1640.19,1652.81,1631.73,1635.95,1644.16,1653.51,1632.1,1639.05,589438
03.04.2020 22:00:00,1635.95,1674.51,1634.91,1669.36,1639.05,1674.9,1635.3,1672.83,643444
03.05.2020 22:00:00,1669.36,1692.1,1641.61,1673.89,1672.83,1692.65,1642.75,1674.46,1005737
03.08.2020 21:00:00,1673.89,1703.19,1656.98,1678.31,1674.46,1703.52,1657.88,1679.2,910166
03.09.2020 21:00:00,1678.31,1680.43,1641.37,1648.71,1679.2,1681.18,1641.94,1649.75,943377
03.10.2020 21:00:00,1648.71,1671.15,1632.9,1634.42,1649.75,1671.56,1633.31,1637.07,793816
03.11.2020 21:00:00,1634.42,1650.28,1560.5,1578.29,1637.07,1650.8,1560.92,1580.01,1009172
03.12.2020 21:00:00,1578.29,1597.85,1504.34,1528.99,1580.01,1598.36,1505.14,1530.09,1052940
03.15.2020 21:00:00,1528.99,1575.2,1451.08,1509.12,1530.09,1576.05,1451.49,1512.94,1196812
03.16.2020 21:00:00,1509.12,1553.91,1465.4,1528.57,1512.94,1554.21,1466.1,1529.43,1079729
03.17.2020 21:00:00,1528.57,1545.93,1472.49,1485.85,1529.43,1546.74,1472.99,1486.75,976857
03.18.2020 21:00:00,1485.85,1500.68,1463.49,1471.89,1486.75,1501.6,1464.64,1474.16,833803
03.19.2020 21:00:00,1471.89,1516.07,1454.46,1497.01,1474.16,1516.57,1455.93,1497.82,721471
03.22.2020 21:00:00,1497.01,1560.86,1482.21,1551.45,1497.82,1561.65,1483.22,1553.09,707830
03.23.2020 21:00:00,1551.45,1631.23,1551.45,1621.05,1553.09,1638.75,1553.09,1631.35,164862
03.24.2020 21:00:00,1621.05,1636.23,1588.82,1615.77,1631.35,1650.03,1601.29,1618.47,205272
03.25.2020 21:00:00,1615.77,1642.96,1587.7,1628.31,1618.47,1649.81,1599.87,1633.29,152804
03.26.2020 21:00:00,1628.31,1630.48,1606.76,1617.5,1633.29,1638.48,1616.9,1622.8,307278
03.29.2020 21:00:00,1617.5,1631.48,1602.51,1620.91,1622.8,1643.86,1612.55,1623.77,291653
03.30.2020 21:00:00,1620.91,1626.55,1573.37,1574.9,1623.77,1627.31,1575.24,1579.1,371507
03.31.2020 21:00:00,1574.9,1600.41,1560.13,1590.13,1579.1,1603.42,1570.75,1592.43,412780
04.01.2020 21:00:00,1590.13,1619.76,1582.42,1612.07,1592.43,1621.1,1583.37,1614.49,704652
04.02.2020 21:00:00,1612.07,1625.21,1605.39,1618.63,1614.49,1626.83,1607.69,1621.37,409490
04.05.2020 21:00:00,1618.63,1668.35,1608.59,1657.77,1621.37,1670.98,1609.7,1663.43,381690
04.06.2020 21:00:00,1657.77,1671.95,1641.84,1644.84,1663.43,1677.53,1643.4,1650.46,286313
04.07.2020 21:00:00,1644.84,1656.39,1640.1,1644.06,1650.46,1657.43,1643.46,1646.66,219464
04.08.2020 21:00:00,1644.06,1689.66,1643.05,1682.16,1646.66,1691.13,1644.83,1686.74,300111
04.12.2020 21:00:00,1682.16,1722.25,1677.35,1709.16,1686.74,1725.48,1680.49,1718.28,280905
04.13.2020 21:00:00,1709.16,1747.04,1708.56,1726.18,1718.28,1748.88,1709.36,1729.72,435098
04.14.2020 21:00:00,1726.18,1730.53,1706.67,1714.35,1729.72,1732.97,1708.95,1717.25,419065
04.15.2020 21:00:00,1714.35,1738.65,1707.83,1715.99,1717.25,1740.35,1708.93,1720.09,615105
04.16.2020 21:00:00,1715.99,1718.46,1677.16,1683.2,1720.09,1720.09,1680.55,1684.97,587875
04.19.2020 21:00:00,1683.2,1702.49,1671.1,1694.71,1684.97,1703.46,1672.02,1697.29,412116
04.20.2020 21:00:00,1694.71,1697.66,1659.42,1683.4,1697.29,1698.44,1662.3,1686.58,502893
04.21.2020 21:00:00,1683.4,1718.21,1679.61,1713.67,1686.58,1719.19,1680.71,1716.91,647622
04.22.2020 21:00:00,1713.67,1738.59,1706.93,1729.89,1716.91,1739.47,1707.72,1731.83,751833
04.23.2020 21:00:00,1729.89,1736.31,1710.56,1726.74,1731.83,1736.98,1711.03,1727.71,608827
04.26.2020 21:00:00,1726.74,1727.55,1705.99,1713.36,1727.71,1728.55,1706.72,1715.29,698217
04.27.2020 21:00:00,1713.36,1716.52,1691.41,1707.66,1715.29,1718.02,1692.51,1710.22,749906
04.28.2020 21:00:00,1707.66,1717.42,1697.65,1711.58,1710.22,1718.57,1698.4,1715.42,630720
04.29.2020 21:00:00,1711.58,1721.94,1681.36,1684.97,1715.42,1722.79,1681.91,1687.92,631609
04.30.2020 21:00:00,1684.97,1705.87,1669.62,1699.92,1687.92,1706.33,1670.81,1701.66,764742
05.03.2020 21:00:00,1699.92,1714.75,1691.46,1700.42,1701.66,1715.83,1692.96,1702.17,355859
05.04.2020 21:00:00,1700.42,1711.64,1688.55,1703.04,1702.17,1712.55,1690.42,1706.71,415576
05.05.2020 21:00:00,1703.04,1708.1,1681.6,1685.18,1706.71,1708.71,1682.33,1688.33,346814
05.06.2020 21:00:00,1685.18,1721.95,1683.59,1715.17,1688.33,1722.53,1684.8,1716.91,379103
05.07.2020 21:00:00,1715.17,1723.54,1701.49,1704.06,1716.91,1724.42,1702.1,1705.25,409225
05.10.2020 21:00:00,1704.06,1712.02,1691.75,1696.68,1705.25,1713.03,1692.45,1697.58,438010
05.11.2020 21:00:00,1696.68,1710.94,1693.56,1701.46,1697.58,1711.31,1693.92,1703.32,369988
05.12.2020 21:00:00,1701.46,1718.11,1698.86,1716.09,1703.32,1718.69,1699.4,1718.63,518107
05.13.2020 21:00:00,1716.09,1736.16,1710.79,1727.71,1718.63,1736.55,1711.33,1731.38,447401
05.14.2020 21:00:00,1727.71,1751.56,1727.71,1743.94,1731.38,1752.1,1728.89,1744.96,561909
05.17.2020 21:00:00,1743.94,1765.3,1727.4,1731.73,1744.96,1765.92,1728.08,1732.99,495628
05.18.2020 21:00:00,1731.73,1747.76,1725.05,1743.52,1732.99,1748.24,1726.29,1746.9,596250
05.19.2020 21:00:00,1743.52,1753.8,1742.04,1747.22,1746.9,1754.28,1742.62,1748.48,497960
05.20.2020 21:00:00,1747.22,1748.7,1717.14,1726.56,1748.48,1751.18,1717.39,1727.82,557122
05.21.2020 21:00:00,1726.56,1740.06,1723.33,1735.67,1727.82,1740.7,1724.41,1736.73,336867
05.24.2020 21:00:00,1735.67,1735.67,1721.61,1727.88,1736.73,1736.73,1721.83,1730.25,164650
05.25.2020 21:00:00,1727.88,1735.39,1708.48,1710.1,1730.25,1735.99,1709.34,1712.21,404914
05.26.2020 21:00:00,1710.1,1715.93,1693.57,1708.36,1712.21,1716.3,1694.04,1709.85,436519
05.27.2020 21:00:00,1708.36,1727.42,1703.41,1717.28,1709.85,1727.93,1705.85,1721.0,416306
05.28.2020 21:00:00,1717.28,1737.58,1712.55,1731.2,1721.0,1738.26,1713.24,1732.07,399698
05.31.2020 21:00:00,1731.2,1744.51,1726.98,1738.73,1732.07,1745.11,1727.93,1742.56,365219

Problem

This is the result for this code and I'm looking for ways to find intersections for SMA20 (yellow) and SMA50 (green) lines and thus able to get alerts whenever these lines cross.

Solution

Print out intersections indication crossing from above or below relative to each series.

import numpy as np

g20=sma20.values
g50=sma50.values
# np.sign(...) return -1, 0 or 1
# np.diff(...) return value difference for (n-1) - n, to obtain intersections
# np.argwhere(...) remove zeros, preserves turning points only
idx20 = np.argwhere(np.diff(np.sign(g20 - g50))).flatten()

priceSma_df.plot()
plt.scatter(close.index[idx20], sma50[idx20], color='red')
plt.show()

Answer 1

import numpy as np

f=close.values
g20=sma20.values
g50=sma50.values
idx20 = np.argwhere(np.diff(np.sign(f - g20))).flatten()
idx50 = np.argwhere(np.diff(np.sign(f - g50))).flatten()

priceSma_df = pd.DataFrame({
  'BidClose' : close,
  'SMA 20' : sma20,
  'SMA 50' : sma50
 })


priceSma_df.plot()
plt.scatter(close.index[idx20], sma20[idx20], color='orange')
plt.scatter(close.index[idx50], sma50[idx50], color='green')
plt.show()