Mrsimulator mrsimulator is an open-source python package for computing fast and versatile solid-state NMR simulator of one-dimensional static, MAS, and VAS spectra of nuclei experiencing chemical shift (nuclear shielding) and quadrupolar coupling interactions. The library is optimized for computing both crystalline and amorphous materials and is compatible with modern python packages, such as scikit-learn, Keras, etc. The core of the mrsimulator library is written in C, wrapped, and made available in python. What's new! ⭐ Improved simulation performance. ⭐. Removed the Dimension class and added a new Method class instead. New methods for simulating the NMR spectrum: BlochDecaySpectrum and BlochDecayCentralTransitionSpectrum. The Bloch decay spectrum method simulates all p=Δm=-1 transition pathways, while the Bloch decay central transition selective spectrum method simulates all transition pathways with p=Δm=-1 and d=0. New Isotope, Transition, and ZeemanState classes. Every class now includes a reduced_dict() method. The reduced_dict method returns a dictionary with minimal key-value pairs required to simulate the spectrum. Note, this may cause metadata loss, if any. Added a label and description attributes to the Site class. Added a new label attribute to the SpinSystem class. New SignalProcessor class for post-simulation signal processing. Improved usage of least-squares minimization using python LMFIT package. Added a new get_spectral_dimensions utility function to extract the spectral dimensions information from the CSDM object. Bug fixes Fixed bug resulting from the rotation of the fourth rank tensor with non-zero euler angles. Fixed bug causing a change in the spectral area as the sampling points change. Now the area is constant. Fixed bug resulting in an incorrect spectrum when non-coincidental quad and shielding tensors are given. Fixed bug causing incorrect generation of transition pathways when multiple events are present. Other changes Renamed the decompose attribute from the ConfigSimulator class to decompose_spectrum. The attribute is an enumeration with the following literals: none: Computes a spectrum which is an integration of the spectra from all spin systems. spin_system: Computes a series of spectra each corresponding to a single spin system. Renamed Isotopomer class to SpinSystem. Renamed isotopomers attribute from Simulator class to spin_systems. Renamed dimensions attribute from Simulator class to methods. Changed the default value of name and description attribute from the SpinSystem class from "" to None.