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Nov 19, 2024, 17:57:17

The <input type="number"> is so evil. I thought that entering 1e309 will have its value return 1e309 and that converting it to a number will give me infinity. Nope, it will return an empty string, and converting it to a number gets me zero. Note that 1e309 IS A VALID FLOATING-POINT NUMBER according to the #HTML standard.

#web #webdev #javascript #coding

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Articles

  • Jan 6, 2020

    Use complex numbers as canonical variables

    In this article, I try exploring an idea: using complex numbers to combine pairs of canonical variables into complex variables: c≔αq+iβp\mathbf c\coloneqq\alpha\mathbf q+\mathrm i\beta\mathbf p. It turns out that we can write canonical equations dcdt=−2iαβ∂H∂c∗\frac{\mathrm d\mathbf c}{\mathrm dt}=-2\mathrm i\alpha\beta\frac{\partial\mathcal H}{\partial\mathbf c^*}, Poisson brackets {f,g}=−2iαβ(∂f∂c⋅∂g∂c∗−∂f∂c∗⋅∂g∂c)\left\{f,g\right\}=-2\mathrm i\alpha\beta \left(\frac{\partial f}{\partial\mathbf c}\cdot \frac{\partial g}{\partial\mathbf c^*}- \frac{\partial f}{\partial\mathbf c^*}\cdot \frac{\partial g}{\partial\mathbf c}\right), and canonical transformations ∂c∗∂c′∗=∂c′∂c,∂c∂c′∗=−∂c′∂c∗\frac{\partial\mathbf c^*}{\partial\mathbf c'^*}= \frac{\partial\mathbf c'}{\partial\mathbf c}, \frac{\partial\mathbf c}{\partial\mathbf c'^*}= -\frac{\partial\mathbf c'}{\partial\mathbf c^*} in these complex numbers. Finally, I show two examples of using them in real problems: a free particle, and a harmonic oscillator.

  • Jan 1, 2020

    Giving birth to my own blog

    This is my first blog! I will share interesting things in my life here.

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